<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>盒子模型边框</title>
    <style>
        .c1{
            width: 200px;
            height: 100px;
            /*实线边框*/
            border-left-style: solid;
            /*虚线边框*/
            border-right-style: dashed;
            /*点状边框*/
            border-top-style: dotted;
            /*双线边框*/
            border-bottom-style: double;
            border-color: red;
            border-width: 10px;
        }
        .c2{
            width: 200px;
            height: 100px;
            border-style: dotted dashed double solid;
            border-color: red green blue purple;
            border-width: 5px 10px 15px 20px;
        }
        .c3{
            width: 200px;
            height: 100px;
            border: solid 1px red;
            /*border-radius: 10px;*/
            border-radius: 10%;
        }
        .c4{
            width: 100px;
            height: 100px;
            border: 1px solid red;
            border-radius: 50%;
        }
    </style>
</head>
<body>
<div class="c1"></div>
<hr>
<div class="c2"></div>
<hr>
<div class="c3"></div>
<hr>
<div class="c4"></div>
</body>
</html>